Pivot joint

Abstract

A pivot joint for a robot, including a double-acting pneumatic pivot actuator, which has a first working chamber with a first working port and a second working chamber with a second working port, and further including a valve arrangement having a first valve group for a selective connection of the first working port to one of a pressurization port and an exhaust port, and having a second valve group for a selective connection of the second working port to one of the pressurization port and the exhaust port. The valve arrangement includes a safety valve which is connected to the first working port and to the second working port and which is configured for blocking a connection between the first working port and the second working port in a blocking position and for releasing the connection between the first working port and the second working port in a release position.

The invention claimed is: 
     
       1. A pivot joint for a robot, comprising:
 a double-acting pneumatic pivot actuator, which has a first working chamber with a first working port and a second working chamber with a second working port, and 
 further comprising a valve arrangement for a safety-related pneumatic control of the pivot actuator, having a first valve group for a selective connection of the first working port to one of a pressurization port and an exhaust port, and having a second valve group for a selective connection of the second working port to one of the pressurization port and the exhaust port, and 
 which valve arrangement comprises a safety valve which is connected to the first working port and to the second working port and which is configured for blocking a connection between the first working port and the second working port in a blocking position and for releasing the connection between the first working port and the second working port in a release position, 
 wherein the safety valve is connected to the exhaust port and is configured to block a connection between the first working port and the second working port and the exhaust port in the blocking position and is configured to release the connection between the first working port and the second working port and the exhaust port in the release position. 
 
     
     
       2. The pivot joint according to  claim 1 , wherein a choke is arranged between the safety valve and the exhaust port. 
     
     
       3. The pivot joint according to  claim 2 , wherein a choke cross section of the choke is larger than a supply cross section of the first valve group and larger than a supply cross section of the second valve group. 
     
     
       4. A pivot joint for a robot, comprising:
 a double-acting pneumatic pivot actuator, which has a first working chamber with a first working port and a second working chamber with a second working port, and 
 further comprising a valve arrangement for a safety-related pneumatic control of the pivot actuator, having a first valve group for a selective connection of the first working port to one of a pressurization port and an exhaust port, and having a second valve group for a selective connection of the second working port to one of the pressurization port and the exhaust port, and 
 which valve arrangement comprises a safety valve which is connected to the first working port and to the second working port and which is configured for blocking a connection between the first working port and the second working port in a blocking position and for releasing the connection between the first working port and the second working port in a release position, 
 wherein the safety valve comprises an actuator acting on a valve member which is movably mounted in a valve housing of the safety valve for switching the valve member between the release position and the blocking position and wherein the safety valve comprises a spring acting on the valve member for prestressing the valve member into the release position. 
 
     
     
       5. The pivot joint according to  claim 4 , comprising a second safety valve which is arranged in parallel to the safety valve. 
     
     
       6. The pivot joint according to  claim 5 , wherein one of the two safety valves is assigned a first control for actuating the actuator of the safety valve, and wherein the other of the two safety valves is assigned a second control for actuating the actuator of this safety valve. 
     
     
       7. The pivot joint according to  claim 6 , wherein the first working port or the first working chamber is assigned a first pressure sensor that provides a first pressure signal to the first control, and wherein the second working port or the second working chamber is assigned a second pressure sensor that provides a second pressure signal to the second control. 
     
     
       8. The pivot joint according to  claim 7 , wherein a brake biased into a braking position and a brake control for switching over the brake between the braking position for the pivot actuator and a release position for the pivot actuator are assigned to the pivot actuator. 
     
     
       9. The pivot joint according to  claim 8 , wherein the brake control and the first valve group and the second valve group and the first control and the second control are each electrically connected to a valve control, which is configured to carry out a test procedure, in which the brake control activates a braking state for the pivoting actuator and in which the first valve group and/or the second valve group enable an asymmetrical pressurization of the pivoting actuator and in which at least one safety valve is switched over from the blocking position into the release position, and in which a pressure change at the first working port and/or at the second working port is monitored.